/*********************************************************************
 * Copyright (C) 2002 Andrew Khan
 * <p>
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * <p>
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * <p>
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.biff.formula;

import jxl.Cell;
import jxl.biff.CellReferenceHelper;
import jxl.biff.IntegerHelper;
import jxl.common.Logger;

/**
 * A cell reference in a formula
 */
class CellReference extends Operand implements ParsedThing {
    /**
     * The logger
     */
    private static Logger logger = Logger.getLogger(CellReference.class);

    /**
     * Indicates whether the column reference is relative or absolute
     */
    private boolean columnRelative;

    /**
     * Indicates whether the row reference is relative or absolute
     */
    private boolean rowRelative;

    /**
     * The column reference
     */
    private int column;

    /**
     * The row reference
     */
    private int row;

    /**
     * The cell containing the formula.  Stored in order to determine
     * relative cell values
     */
    private Cell relativeTo;

    /**
     * Constructor
     *
     * @param rt the cell containing the formula
     */
    public CellReference(Cell rt) {
        relativeTo = rt;
    }

    /**
     * Constructor
     */
    public CellReference() {
    }

    /**
     * Constructor invoked when parsing a text string
     *
     * @param s the string being parsed
     */
    public CellReference(String s) {
        column = CellReferenceHelper.getColumn(s);
        row = CellReferenceHelper.getRow(s);
        columnRelative = CellReferenceHelper.isColumnRelative(s);
        rowRelative = CellReferenceHelper.isRowRelative(s);
    }

    /**
     * Reads the ptg data from the array starting at the specified position
     *
     * @param data the RPN array
     * @param pos the current position in the array, excluding the ptg identifier
     * @return the number of bytes read
     */
    public int read(byte[] data, int pos) {
        row = IntegerHelper.getInt(data[pos], data[pos + 1]);
        int columnMask = IntegerHelper.getInt(data[pos + 2], data[pos + 3]);
        column = columnMask & 0x00ff;
        columnRelative = ((columnMask & 0x4000) != 0);
        rowRelative = ((columnMask & 0x8000) != 0);

        return 4;
    }

    /**
     * Accessor for the column
     *
     * @return the column
     */
    public int getColumn() {
        return column;
    }

    /**
     * Accessor for the row
     *
     * @return the row
     */
    public int getRow() {
        return row;
    }

    /**
     * Gets the cell reference as a string for this item
     *
     * @param buf the string buffer to populate
     */
    public void getString(StringBuffer buf) {
        CellReferenceHelper.getCellReference(column, !columnRelative,
                row, !rowRelative,
                buf);
    }

    /**
     * Gets the token representation of this item in RPN
     *
     * @return the bytes applicable to this formula
     */
    byte[] getBytes() {
        byte[] data = new byte[5];
        data[0] = !useAlternateCode() ? Token.REF.getCode() :
                Token.REF.getCode2();

        IntegerHelper.getTwoBytes(row, data, 1);

        int grcol = column;

        // Set the row/column relative bits if applicable
        if (rowRelative) {
            grcol |= 0x8000;
        }

        if (columnRelative) {
            grcol |= 0x4000;
        }

        IntegerHelper.getTwoBytes(grcol, data, 3);

        return data;
    }

    /**
     * Adjusts all the relative cell references in this formula by the
     * amount specified.  Used when copying formulas
     *
     * @param colAdjust the amount to add on to each relative cell reference
     * @param rowAdjust the amount to add on to each relative row reference
     */
    public void adjustRelativeCellReferences(int colAdjust, int rowAdjust) {
        if (columnRelative) {
            column += colAdjust;
        }

        if (rowRelative) {
            row += rowAdjust;
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex the sheet on which the column was inserted
     * @param col the column number which was inserted
     * @param currentSheet TRUE if this formula is on the sheet in which the
     * column was inserted, FALSE otherwise
     */
    public void columnInserted(int sheetIndex, int col, boolean currentSheet) {
        if (!currentSheet) {
            return;
        }

        if (column >= col) {
            column++;
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex the sheet on which the column was removed
     * @param col the column number which was removed
     * @param currentSheet TRUE if this formula is on the sheet in which the
     * column was inserted, FALSE otherwise
     */
    void columnRemoved(int sheetIndex, int col, boolean currentSheet) {
        if (!currentSheet) {
            return;
        }

        if (column >= col) {
            column--;
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex the sheet on which the row was inserted
     * @param r the row number which was inserted
     * @param currentSheet TRUE if this formula is on the sheet in which the
     * column was inserted, FALSE otherwise
     */
    void rowInserted(int sheetIndex, int r, boolean currentSheet) {
        if (!currentSheet) {
            return;
        }

        if (row >= r) {
            row++;
        }
    }

    /**
     * Called when a column is inserted on the specified sheet.  Tells
     * the formula  parser to update all of its cell references beyond this
     * column
     *
     * @param sheetIndex the sheet on which the row was removed
     * @param r the row number which was removed
     * @param currentSheet TRUE if this formula is on the sheet in which the
     * column was inserted, FALSE otherwise
     */
    void rowRemoved(int sheetIndex, int r, boolean currentSheet) {
        if (!currentSheet) {
            return;
        }

        if (row >= r) {
            row--;
        }
    }

    /**
     * If this formula was on an imported sheet, check that
     * cell references to another sheet are warned appropriately
     * Flags the formula as invalid
     * Does nothing here
     */
    void handleImportedCellReferences() {
    }
}
